Page 155 - Welding Robots Technology, System Issues, and Applications

142 Welding Robots
command requires a previous definition of the welding parameters, because it
executes welding trajectories, but since the values of those parameters are kept,
there’s no need to send them again between two consecutive production cycles if
they aren’t to be changed.

Command “automatic mode”
Connect
Send message: variable_write decision1 num 9000
Close

Finally, it should be emphasized that the welding parameters can be adjusted
without restrictions at any time during “automatic mode” (a service implemented
in task 1), since those are calls to the TCP/IP services running in a different task
(task 2).

4.8 Chapter Final Notes

In this chapter several system issues related to robotic welding were discussed with
the triple objective to:

1. Clarify: robotic welding is very demanding on system resources and
capabilities mainly because automatic welding is a task that requires an
adapting behavior of the automatic system [19],[23]. This has an
enormous impact on the requirements for the system planned to make the
welding task automatic. First because the system needs to handle the
welding process models (databases and/or knowledge base [45]) to enable
automatic selection of the welding parameters and their dynamic behavior
based on the observed welding conditions. Second because the automatic
system needs to accommodate the advanced sensors used to obtain that
information, but also to perform seam tracking, inspection and quality
analysis. The required sub-systems and software modules necessary to
incorporate information from sensors must be flexible enough to allow
multiple sensors to be integrated easily and be fully explored.
2. Contribute: to cope with the robotic welding requirements there are
several features from the robot controllers that can be used, along with
available software architectures, software component technologies,
communication data and signal protocols, sensors and interfaces, etc. The
choice is up to the system engineers to select from the available
possibilities, although a few standard approaches are obvious candidates
as this chapter clearly pointed out. Any adopted solution should use a
software framework capable of handling local and remote services with
the objective of incorporating the necessary functionalities using currently
available industrial standards.
3. Demonstrate: in this chapter a software architecture was defined (Figure
4.9) and several examples on using it were given with the objective of